In order to lift up liquids deposited in the ground, for example petroleum, frequent use is made of deep well pumps whose cylinder with foot valve is connected to the tubing and installed in the borehole. The pump piston of such a deep well pump is suspended from a sucker-rod string which is kept in periodic up and down motions by means of a deep-well pump drive above ground.
The oil field pumping unit drive consists of a support framework on which the walking beam is pivoted by means of a rocker bearing. One end of the walking beam is connected to a crank assembly which moves this end of the walking beam up and down. This motion is transferred by the walking beam to the pump linkage which is fastened by means of the wireline hanger to the horse head which is mounted on the free end of the walking beam. The curve track of the horse head is laid out so that the suspension cable unrolling on it is always vertically above the center of the borehole.
For inspection of the tubing pump it is occasionally necessary to remove the wireline hanger and the well tubing connected with the oil well tubing pump. To perform this work, the horse head must be removed from the walking beam or displaced along it so far that the hoisting equipment of the disassembly device workover rig can travel vertically up and down above the borehole. For this purpose, it is necessary that a maintenance man climbs onto the walking beam from a ladder and moves astride the beam unit; reaching the horse head in order to loosen its locking arrangement. When installing the horse head, the same procedure must be used.
Since this type of disassembly and assembly of the horse head involves considerable hazard, attempts have been made to eliminate this hazard, and accordingly it is an object of the present invention to provide for improvements in eliminating the hazard.
Another object of the present invention is to provide an arrangement, of the foregoing character, which is substantially simple in construction and may be economically fabricated.
A further object of the present invention is to provide an arrangement, as described, which may be readily maintained in service and which has a substantially long operating life.